[HLUG] generate a guid

[Sarah Chard]

Hi 

I use gnucash for my accounts and having uprated to ubuntu 12.04 the
gnucash is also a newer version.
I have for several years been using a custom report  which generates the
figures for my vat returns and makes life so much easier! It's not
included in the main reports I have to install it myself.
 It's an equile script and reading through the gnucash documentation it
looks as if it will work in this version but i need to generate a guid -
which the documentation tells me is 
' a unique, cryptographically random 128-bit value.'
how should i do this?
-- 
Sarah